Communication receiver systems that rely on receiving radio frequency signals are dependent on certain characteristics of the antenna used, in order to ensure correct operation. One such parameter, for example, may be the antenna impedance. If the impedance between the receiver and the antenna is not matched, the feed line may generate reflections at such unmatched impedance interfaces, reflecting the received signal back towards the source. This may generate so-called standing waves and reduces the effective power transfer from the antenna to the receiving device.
Another factor that may impact the operation of a receiver may be variations due to manufacturing. In particular for small antennas and/or antennas that may be operated in physically constrained spaces, small changes in the operating environment may impact the antenna characteristics. For example, small antennas on Printed Circuit Boards (PCBs) may exhibit relatively large sample variation. In addition, due to the close proximity of a PCB antenna with other circuitry, there may be some electromagnetic coupling that may affect the antenna performance. Furthermore, antennas from different manufacturers may also differ in their characteristics.
Antennas generally respond differently at different frequencies. For example, the antenna gain may be frequency dependent. Also, changes in the operating environment, for example temperature, may affect the circuit-antenna matching.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.